1. Field of the Invention
The present invention relates to a transport apparatus capable, for example, of holding or bearing a heavy object, in particular, a heavy article weighing 1 ton or more, such as a heavy load, product, or workpiece (hereinafter referred to as an “article”), setting it at a predetermined position (i.e., setting it in position), or bearing a robot.
2. Related Background Art
A transport apparatus (a handling robot or a material handling apparatus) has been available which, for example, moves an article within a plant, loads and unloads an article on and from a truck, or transfers an article transported by a conveyor onto another conveyor. Conventional examples of such a transport apparatus include an articulated six-axis robot and the transport apparatus by the present applicant (JP 3077753 B).
A positioning apparatus (a positioner) for setting an article at the operating position (i.e., setting it in position) for a welding robot, a coating robot, or the like has also been available. An example of the positioner is the positioning apparatus by the present applicant (JP 3026790 B).
While it is of an articulated six-axis type, a conventional handling robot has a main body that is stationary, which means it is incapable of moving longitudinally or laterally; its arm, which rotates, has its limitations in rotation range. Further, while the robot arm is capable of vertical rotation, the robot main body does not extend upwardly, so that there are limitations regarding the upward movable range. Thus, the conventional handling robot is generally restricted in its movable range.
In a conventional articulated six-arm robot, its arm is directly mounted to a reduction gear constituting the drive source thereof, so that the load on the arm is directly applied to the reduction gear, which means the reduction gear has to bear the burden, so that this robot is not suitable for the transport of a heavy object, in particular, an object weighing as much as 1 ton or more. The maximum weight that can be borne by the robots on the market is 750 kg.
While free from any particular problems, the transport apparatus of JP 3077753 B and the positioning apparatus of JP 3026790 B have been respectively developed mainly for the purposes of the transport of an article and the positioning of an article, which means neither of them is suited for conducting both transport and positioning alone.